Yuerlita,Asian Institute of Technology |
Yuerlita,Andalas University |
Perret S.R.,UMR G Eau |
Shivakoti G.P.,Asian Institute of Technology
Environmental Management | Year: 2013
Technical and socio-economic characteristics are known to determine different types of fishers and their livelihood strategies. Faced with declining fish and water resources, small-scale fisheries engage into transformations in livelihood and fishing practices. The paper is an attempt to understand these changes and their socio-economic patterns, in the case of Singkarak Lake in West Sumatra, Indonesia. Based upon the hypothesis that riparian communities have diverse, complex yet structured and dynamic livelihood systems, the paper's main objective is to study, document and model the actual diversity in livelihood, practices and performance of inland small-scale fisheries along the Singkarak Lake, to picture how households are adapted to the situation, and propose an updated, workable model (typology) of those for policy. Principal component analysis and cluster analysis were used to develop a typology of fishing households. The results show that small-scale fishers can be classified into different types characterized by distinct livelihood strategies. Three household types are identified, namely "farming fishers" households (type I, 30 %), "fishing farmers" households (type II, 30 %), and "mainly fishers" households (type III, 40 %). There are significant differences among these groups in the number of boats owned, annual fishing income, agriculture income and farming experience. Type I consists of farming fishers, well equipped, with high fishing costs and income, yet with the lowest return on fishing assets. They are also landowners with farming income, showing the lowest return on land capital. Type II includes poor fishing farmers, landowners with higher farming income; they show the highest return on land asset. They have less fishing equipment, costs and income. Type III (mainly fishers) consists of poorer, younger fishers, with highest return on fishing assets and on fishing costs. They have little land, low farming income, and diversified livelihood sources. The nature of their livelihood strategies is discussed for each identified group. This helps to understand the complexity and diversity of small-scale fishers, particularly in the study area which is still poorly known. This paper concludes with policy implication and possible management initiatives for environmentally prudent policy aiming at improvement of fishers' livelihood. © 2013 Springer Science+Business Media New York.
Jayathilaka P.M.S.,Ministry of Finance and Planning |
Soni P.,Asian Institute of Technology |
Perret S.R.,UMR G Eau |
Jayasuriya H.P.W.,Sultan Qaboos University |
Salokhe V.M.,Assam University
Regional Environmental Change | Year: 2012
Climate change is the main global challenge of this century; it is therefore imperative to identify its effects on agriculture in developing countries. This research makes spatial assessment of climate change effect on major plantation crops in Sri Lanka, with emphasis on crop suitability of tea, rubber, and coconut. Geo-referenced maps of spatial and temporal changes in crop suitability and production potentials are generated and compared. Data pertaining to six agro-ecological zones under the study area are analyzed for a period of 1980-2007. Crop suitability maps are generated amalgamating yield maps and climatic factors maps using AHP in multi-criteria analysis under two time frames of 1980-1992 and 1993-2007. Percent change in crop suitability and crop yield classes is calculated based on five crop suitability and five crop yield classes during two time frames. Dynamics of climatic parameters and crop yield are recognized using geo-referenced maps. The suitability maps of the two time frames are compared to identify the changes with each crop in conjunction with changes in the prevailing climate and yield. Geographic shift of suitability, yield, and climate classes are examined. Net gain or loss in crop production is quantified. Long-term annual rainfall significantly decreased in mid-country wet zone, whereas the mean temperature of the study area increased by 1. 4°C. Results clearly showed that the climate and yield can be meaningfully related to the crop suitability and management. © 2011 Springer-Verlag.
Molle B.,Irtsea |
Tomas S.,Irtsea |
Huet L.,Irtsea |
Audouard M.,UMR G Eau |
And 2 more authors.
Journal of Irrigation and Drainage Engineering | Year: 2016
Treated wastewater reuse (TWWR) offers a promising solution for farm crop and turf irrigation while also mitigating the environmental pressures resulting from effluent disposal in the environment. Most attention is devoted to ensuring that treatments are safe for human health. Nevertheless, the treatment may be incomplete or some pathogens resulting from biofilm development may be dispersed through the system. Therefore, end-users must take specific precautions and implement practices to prevent any unintended dispersal of contaminants transported by the water, in particular when using sprinkler irrigation practices. To generate data to evaluate dissemination hazards, and thereby facilitate risk calculation, a sprinkler was operated in (windy) field conditions and the wetted area drift as well as the transport of small particles downwind was measured within a perimeter 4 times the sprinkler range. The volumes collected at such distances on the ground and along the wind axis remained below 0.5 mLm-2 h-1, and below 4 mLh-1 perm2 of vertical section, for winds of 5 ms-1, and below 0.25 and 1.4 mLh-1 perm2 of vertical section for winds of 3 ms-1. The measurement method, based on the use of fluorescent dye, is proposed along with an empirical model that can be used to estimate the volumes of potentially contaminated water that can escape from the wetted zone under wind influence for the specific sprinkler used. © 2016 American Society of Civil Engineers.
Poncet J.,UMR G EAU |
Poncet J.,CIRAD - Agricultural Research for Development |
Kuper M.,Umr G eau |
Kuper M.,CIRAD - Agricultural Research for Development |
Chiche J.,Hassan II Institute for Agronomy and Veterinary Medicine
Agricultural Systems | Year: 2010
For many years, large-scale irrigation around the world was based on state-driven water management and on a planned innovation process and diffusionist extension services. The purpose of this study is to show that formal extension services are not the only intermediaries of innovation and that local innovations take place at the initiative of farmers even in state-driven irrigation schemes. The study addressed changes in farming systems in a large-scale irrigation scheme in Morocco from two angles: a review of planned innovations and analysis of the actual innovation process at the village level. We show that the implementation of the large-scale irrigation scheme contributed to agricultural development, but often indirectly, and that it was not the only source of innovation. We also show how these results support recent thinking on innovation systems. Today, informal labour, neighbour and marketing networks are the main innovation intermediaries. New practices in agricultural extension are required to facilitate local innovations and to link farmers to more global innovation networks. © 2009 Elsevier Ltd. All rights reserved.
Cassan L.,CNRS Fluid Dynamics Institute of Toulouse |
Belaud G.,UMR G EAU |
Baume J.P.,UMR G EAU |
Dejean C.,UMR G EAU |
Moulin F.,CNRS Fluid Dynamics Institute of Toulouse
Environmental Fluid Mechanics | Year: 2015
Most of the studies regarding vegetation effects on velocity profiles are based on laboratory experiments. The main focus of this paper is to show how the laboratory knowledge established for submerged vegetation applies to real-scale systems affected by vegetation growth (mainly Ranunculus fluitans). To do so, experiments are conducted at two gage stations of an operational irrigation system. The analysis of first- and second-order fluctuations of velocities is based on field measurements performed by micro-acoustic doppler velocimeter during 8 months, completed with flow measurement campaigns in different seasons. The Reynolds stresses are used to determine shear velocities and deflected plant heights. Then, the modified log–wake law (MLWL), initially derived from laboratory flume experiments, is applied with a unique parametrisation for the whole set of velocity profiles. The MLWL, along with a lateral distribution function, is used to calculate the discharge and to show the influence of vegetation height on the stage–discharge relationships. © 2015, Springer Science+Business Media Dordrecht.
Roy G.,IRSTEA |
Paquier A.,IRSTEA |
Belaud G.,UMR G EAU |
Baume J.P.,UMR G EAU
River Flow 2012 - Proceedings of the International Conference on Fluvial Hydraulics | Year: 2012
The inner delta of Niger River, a large floodplain of about 30,000 km 2, is flooded every year. Building a hydraulic model is essential to analyze the possible evolutions of the flooded areas, which should be affected by large projects or climate change. The main challenge is to get a DEM accurate enough for hydraulic modelling. The DEM obtained from SRTM provides the ground elevation on a grid 90m * 90 m. In order to describe the channel geometry, this DEM must be combined with cross-sections coming from ground topographical survey. This main network is essentially described by its capacity to evacuate the flood. In the floodplain, the mesh is built to respect the main network. Applying a 1 kilometer side cell in average limits the number of cells and the calculation time. A first test was carried out on the South Eastern part of the Niger delta. Calculation shows a right pattern during the 2000-2001 hydrological events, showing a correct location of overflows and a right propagation in the flood plain. © 2012 Taylor & Francis Group.
Dionnet M.,Lisode |
Daniell K.A.,Australian National University |
Imache A.,Lisode |
von Korff Y.,Lisode |
And 5 more authors.
Ecology and Society | Year: 2013
Stakeholder and public participation in natural resources management (NRM) is now widely accepted as necessary to achieve sustainable development outcomes. Yet, effective implementation of participatory processes necessitates wellcalibrated methods and tools, as well as carefully honed facilitation skills that are difficult to gain without practice. Practitioners and academics leading these processes are thus encouraged to better reflect on, prepare, and justify their interventions, before starting to work in the field with stakeholders. Our paper shows how a Simulation Community of Practice (SCoP) was set up to support improved participatory practice. The specificity of this community is that its members not only discuss planned participatory interventions, but also simulate these processes by adopting roles of future participants, and by working through the different steps of the workshop that will be later implemented in the field. The evaluation of our approach shows that individual and social learning of participants in the SCoP is developed, leading mainly to improved facilitator skills and to calibration of the participatory methods and tools being tested. A space is also provided for deepening reflection on the purposes of the participatory process and the values that guide these interventions. Our experience could provide a model for others around the world to set up their own SCoP to support participatory NRM practice. Further improvements to our SCoP and new ones could be made by enhancing the feedback mechanisms between the field sites and the community, in order to encourage more cumulative learning and to reinforce the members' interest, maintaining their involvement in the community over time. © 2013 by the author(s).
Dorchies D.,UMR G EAU |
Malaterre P.-O.,UMR G EAU
Operations Research/ Computer Science Interfaces Series | Year: 2015
The underlining philosophical statement of this chapter is that the promotion of automatic control for open-channel hydraulic systems will be greatly facilitated when simple algorithms and tuning procedures are available and adapted to this type of systems. The objective is therefore to contribute to an “automation for hydraulic systems for dummies” approach. In this chapter, we propose an automatic method to tune a series of distant downstream PI controllers for a cascade of pools. The methodology we present could also be used for local upstream controllers, with minor changes. The method is based on the Auto-Tuned Variation principle (ATV) carrying out a relay experiment. The information obtained from this experiment allows to estimate the parameters of a simplified integrator-delay model of each pool. Finally this allows tuning automatically a series of feedback PI controllers, with given gain and phase robustnessmargins, and a feedforward controller based on simple time delay. This relay experiment is performed for each pool of the canal or river, in sequence, with automatic activation of the previously tuned PI controllers. Different decoupling configurations, in order to reduce interactions between pools, are evaluated in simulation on the benchmark canal 2 of the ASCE Task Committee on Canal Automation Algorithms. © Springer International Publishing Switzerland 2015